Method for preventing metal-liquid explosions in casting operation



1968 R. J MADDIGAN METHOD FOR PREVENTING METAL-LIQUID EXPLOSIONS IN CASTING OPERATION Filed Oct. 22, 1965 INVENTOR. RICHARD J. MADDIGAN BY I ATTORNEY United States Patent 3,368,607 METHOD FOR PREVENTING METAL-LIQUID EXPLOSIONS IN CASTING OPERATION Richard J. Maddigan, Kensington, Calif., assignor to Kaiser Aluminum & Chemical Corporation, Oakland, Califi, a corporation of Delaware Filed Oct. 22, 1965, Ser. No. 500,516 1 Claim. (Cl. 164-1) ABSTRACT OF THE DISCLOSURE This disclosure relates to a method for preventing metal-liquid explosions in a casting operation wherein a liquid spray is used to cool the metal and liquid is thereafter collected in a sump below the casting apparatus. The method comprises mounting a support in the sump above the liquid level therein and below the casting apparatus, and placing a liquid-permeable filter on the support in the sump above the liquid level and below the casting apparatus. Thus, in this arrangement, liquid and droplets of molten metal will pass through the liquidpermeable filter in a fine dispersion while a mass of molten metal will collect and solidify 0n the surface of the filter instead of passing through and reaching the body of liquid therebelow, whereby a metal-liquid explosion is prevented.

The present invention relates to the casting of metal. More particularly, it is concerned with an improved method for preventing metal-liquid explosions during the continuous casting of metal, said method being particularly adaptable to the continuous casting of metal rod, sheet, bar or strip by the traveling or moving mold method wherein the mold cavity is continuously formed by the surfaces of elements such as continuous metal bands and casting wheels.

In the rotating wheel version of the moving mold method of casting metal rod or strip, molten metal is poured into a mold which consists of a rotating wheel having a peripheral channel in combination with a metal band which co-operates with the channel over a portion of its length to constitute a cover therefor. In this method, the molten metal is usually poured at a point near the top of the Wheel into the covered channel, the metal is carried by the rotating wheel through a spray of cooling liquid causing it to substantially solidify and it is then removed from the wheel and carried away on a continuous conveyor system. This is a conventional arrangement for continuously casting metal rod, sheet, bar, or strip and there are a number of known alternative arrangements of the casting wheel. The present invention is applicable to all such constructions, and is applicable to the castings of metal in general.

The problem to which the instant invention is directed has to do with the possibility of metal splashing down off the rotating casting wheel and into the sump below the wheel wherein the cooling water or other liquid collects. If the metal should trap some liquid underneath it in the sump, the water or liquid will be vaporized from the heat of the metal and expand explosively lifting a large slug of liquid and metal into the air. This mass of hot liquid and metal could seriously injure the operating personnel at the casting station as Well as possibly doing some damage to the casting equipment itself.

Accordingly, the instant invention is directed to a method for providing a safety guard which will effectively prevent any explosive contact of liquid and hot molten metal at a casting station. It is an advantage of the method of the instant application that it does this without requiring any substantial modification of the casting equipment and can be used upon any existing casting equipment wherein the cooling liquid collects in a sump below the casting apparatus. It is a further advantage of the method of this application that the safety guard is readily replaceable when its effectiveness is decreased because of use.

These and other purposes and advantages of the instant invention will become more apparent from a review of the following detailed description taken in conjunction with the accompanying drawings. This invention relates to a method for preventing metal-liquid explosions in a casting operation wherein a liquid spray is used to cool the metal and the liquid is thereafter collected in a sump below the casting apparatus. The method comprises mounting a support in the sump above the liquid level therein and below the casting apparatus, and placing a liquid permeable filter on the support in the sump above the liquid level and below the casting apparatus. Thus, in this arrangement, liquid and droplets of molten metal will pass through the liquid permeable filter in a fine dispersion while a mass of molten metal will collect and solidify on the surface of the filter instead of passing through and reaching the body of liquid therebelow, whereby a metal-liquid explosion is prevented.

The accompanying drawings illustrate a presently preferred embodiment of the method of this invention as applied to a rotating wheel continuous casting apparatus.

FIG. 1 is a side elevational view of a simplified representation of a rotating wheel continuous casting device embodying the principles of this invention.

FIG. 2 is an isometric view of a portion of the safety device shown in FIG. 1 and more clearly indicating the arrangement of its components.

With reference now to FIG. 1, furnace 10 contains hot molten metal, for example molten aluminum. The hot molten metal from furnace 10 is transferred via spout 12 into peripheral channel 14 of casting wheel 16 below endless band 17 which co-operates with channel 14 over a portion of its length to constitute a cover therefor. Casting wheel 16 is mounted by means of support plate 18 on base 20. Endless band 17 is kept taut and moved by pulley 19 which is rotated by suitable drive means not shown. Casting wheel 16 is rotated by any suitable means for example by the movement of endless band 17. As the casting wheel 16 rotates, the molten metal collected on the surface thereof passes beneath spray nozzles 22 where it is sprayed with liquid which cools the metal and solidifies the same. The solidified metal 24 is then deflected slightly to one, side to escape the loop of endless band 17 and is transferred away from the casting station for further processing. The liquid after it has been used to cool the metal on casting wheel 16 collects in sump 26 which is below the casting apparatus. As needed, the liquid is drained ofi through drain line 28. In accordance with the practice of this invention, a support, for example grating 30, is positioned in sump 26 above the liquid level therein and below the casting apparatus. A liquid permeable filter for example fine mesh screen 32 is placed on the support grating 30 in sump 26 above the liquid level and below the casting apparatus. In operation, should droplets of metal splash down off the casting wheel 16 into the liquid sump 26, the liquid and droplets of molten metal will pass through the filter screen 32 in a fine dispersion. Should a large slug or mass of molten metal fall off casting wheel 16 into the sump 26, the mass of molten metal will collect and solidify on the surfaces of the filter screen 32 and not reach the liquid collected below. Thus, the possibility of a liquid metal explosion is effectively prevented. FIG. 2 shows a portion of the grating 30 screen 32 arrangement of FIG. 1 to more clearly indicate the positioning of the two components.

It should be apparent that materials other than grating 30 and fine mesh screen 32 may be used in successfully practicing method of this invention. Any suitable liquid permeable filter medium may be used and any appropriate support for such a filter medium may be positioned in the sump 26 of the casting apparatus. For example, the screen may be of metal or woven fiberglass, or even woven asbestos or other similar materials. Still another suitable type of liquid permeable filter that might be used is a mat. The mat may be, for example, steel wool, fiberglass, asbestos, or any other suitable material. Or the liquid permeable filter might be a filter bed of particulate material such as particulate alumina, particulate glass, or particulate metal.

In all cases, the method of this invention effectively prevents a liquid-metal explosion. After a metal spill onto the filter medium, the filter could be removed, the metal melted off and the filter reused. An additional advantage is that a build up of metal in sump 26 will not take place and the normally laborious job of clean-up is simpler and faster. Down time on the casting unit is thereby reduced.

While there has been shown and described hereinabove a presently preferred embodiment for the practice of the method of this invention, it is to be understood that the method of this invention is not limited thereto and that various changes, alterations, and modifications can be made thereto without departing from the spirit and scope thereof as defined in the appended claim, wherein:

What is claimed is:

1. A method for preventing metal-liquid explosions in a casting operation wherein a liquid spray is used to cool the metal and the liquid is thereafter collected in a sump 5 below the casting apparatus comprising:

(a) mounting a support in the sump above the liquid level and below the casting apparatus; (b) placing a liquid permeable filter on the support in the sump above the liquid level and below the casting apparatus so that liquid and droplets of molten metal will pass therethrough in a fine dispersion while a mass of molten metal will collect and solidify on the surfaces of the filter whereby a metalliquid explosion is prevented.

References Cited UNITED STATES PATENTS I. SPENCER OVERHOLSER, Primary Examiner.

R. S. ANNEAR, Assistant Examiner. 

